One-pot access to 2-oxazolines via a Castro-Stephens coupling and intramolecular cyclization

2021 ◽  
Vol 08 ◽  
Author(s):  
Dnyaneshwar Nighot ◽  
Arvind Kumar Jain ◽  
Imran Ali ◽  
Varun Rawat

Aim: Here, we have reported easy one-pot access to a series of oxazolines using a modified Castro-Stephens coupling protocol. Background: 2-oxazolines have been shown to have significant biological activity and wide-ranging applications in organic chemistry. These properties make oxazolines as heterocyclic compounds of immense importance. Objective: The objective of this study is to synthesize oxazoline derivatives via an economical and one-pot protocol. Method: 2-oxazoline has been synthesized through Cu-powder mediated Castro-Stephens coupling and intramolecular cyclization route. The mechanism involves a rearrangement in which one of the oxygen from the N-acylamino alcohol group is liberated as water and then transferred to alkyne functionality to form 2-oxazoline derivatives. The oxazolines were characterized by NMR, mass, and XRD studies. Result: The protocol is economically viable and uses readily available Cu-powder along with DMF for cross-coupling and cyclization steps.

2019 ◽  
Author(s):  
Victor Bloemendal ◽  
Floris P. J. T. Rutjes ◽  
Thomas J. Boltje ◽  
Daan Sondag ◽  
Hidde Elferink ◽  
...  

<p>In this manuscript we describe a modular pathway to synthesize biologically relevant (–)-<i>trans</i>-Δ<sup>8</sup>-THC derivatives, which can be used to modulate the pharmacologically important CB<sub>1</sub> and CB<sub>2</sub> receptors. This pathway involves a one-pot Friedel-Crafts alkylation/cyclization protocol, followed by Suzuki-Miyaura cross-coupling reactions and gives rise to a series of new Δ<sup>8</sup>-THC derivatives. In addition, we demonstrate using extensive NMR evidence that similar halide-substituted Friedel-Crafts alkylation/cyclization products in previous articles were wrongly assigned as the para-isomers, which also has consequence for the assignment of the subsequent cross-coupled products and interpretation of their biological activity. </p> <p>Considering the importance of the availability of THC derivatives in medicinal chemistry research and the fact that previously synthesized compounds were wrongly assigned, we feel this research is describing a straightforward pathway into new cannabinoids.</p>


2020 ◽  
Vol 23 (22) ◽  
pp. 2469-2488 ◽  
Author(s):  
Majid M. Heravi ◽  
Masoumeh Malmir ◽  
Razieh Moradi

: The palladium-catalyzed reaction of aryl halide and boronic acid for the formation of C–C bonds so-called Suzuki–Miyaura cross-coupling reaction has many applications in Modern Synthetic Organic Chemistry. In 2013, we emphasized the applications of the intramolecular Suzuki cross-coupling reaction in cyclization and heterocyclization. Due to a plethora relevant papers appeared in the chemical literature, herein, we wish to cover by updating our previous review, the applications of the intramolecular Suzuki cross-coupling reaction in cyclization and heterocyclization leading to various homocyclic and heterocyclic compounds reported during a period of 2013 to 2018.


2020 ◽  
Vol 24 (22) ◽  
pp. 2566-2587
Author(s):  
Geetika Patel ◽  
Subhash Banerjee

The literature survey reveals that the individual coumarin and heterocyclic molecules have biological and pharmaceutical activities. Moreover, integrated coumarinfused heterocyclic compounds have shown interesting biological and physiochemical properties and thus, designing and development of coumarin-fused heterocyclic molecules are of great interest in the field of synthetic organic chemistry. Several coumarin-fused heterocyclic molecules have been synthesized by using different strategies such as multistep method, one-pot multi-component protocol, coupling and condensation method. The wide applications of integrated coumarin-fused heterocyclic molecules stimulated interest among researchers to develop different methodologies for the synthesis of novel fused molecules. As a consequence, several research articles, papers and review articles have been published in the literature. In this review article, we have presented various methods for the synthesis of different class of coumarin-fused heterocyclic molecules and their applications in chemical, optical, pharmaceutical and other useful applications.


2021 ◽  
Author(s):  
Saideh Rajai-Daryasarei ◽  
Mohammad Hossein Gohari ◽  
Narges Mohammadi

The preparation of heterocyclic compounds has attracted great attention in organic chemistry because of their extensive presence in bioactive molecules, material sciences, and natural products. Accordingly, the straightforward design and...


Synthesis ◽  
2021 ◽  
Author(s):  
Akira Nakamura ◽  
Kouhei Yamamoto ◽  
Ryo Murakami ◽  
Norihito Kawashita ◽  
Kouichi Matsumoto ◽  
...  

A method for synthesizing six-membered heterocyclic compounds was developed based on the features of O,P-acetals. Sequential reactions of intramolecular cyclization between the methylene carbon atom of O,P-acetal and its electrophilic functional group (ester or protected carbamate) was followed by Horner-Wadsworth-Emmons (HWE) olefination with various aldehydes. The developed one-pot method yielded isochroman-4-one and benzoxazin-3-one derivatives with an alkylidene moiety.


Author(s):  
Adnan Cetin

: The heterocyclic compounds are the building blocks for synthesis of the different biological active compounds in the organic chemistry. Heterocyclic compounds have versatile synthetic applicability and biological activity. Pyrazole carboxylic acid derivatives are significant scaffold structures in heterocyclic compounds due to biologic activities such as antimicrobial, anticancer, inflammatory, antidepressant, antifungal anti-tubercular and antiviral etc. The aim of this mini-review is an overview synthesis of pyrazole carboxylic acid derivatives and their biologic applications. The summarized literature survey presents in detail biological activities of pyrazole carboxylic acid derivatives and their various synthetic methods. This mini-review can be guide to many scientists in medicinal chemistry.


Synthesis ◽  
2017 ◽  
Vol 49 (12) ◽  
pp. 2775-2785 ◽  
Author(s):  
Fanny Mathias ◽  
Youssef Kabri ◽  
Maxime Crozet ◽  
Patrice Vanelle

A one-pot sequential intramolecular cyclization and Suzuki–Miyaura or Sonogashira reaction under microwave irradiation are reported in the 5-nitro-2,3-dihydroimidazo[2,1-b]oxazole series. The intramolecular cyclization of 1-(2,4-dibromo-5-nitro-1H-imidazol-1-yl)propan-2-ol between the hydroxyethyl group and the bromine atom at the 2-position is carried out first, followed by optimization and generalization of the Suzuki–Miyaura and Sonogashira cross-coupling reactions of the bromine atom at the 4-position. The various boronic acids and alkynyl derivatives used to perform these palladium-catalyzed cross-coupling reactions allowed to substitute the 6-position of 5-nitro-2,3-dihydroimidazo[2,1-b]oxazole compounds.


2019 ◽  
Author(s):  
Victor Bloemendal ◽  
Floris P. J. T. Rutjes ◽  
Thomas J. Boltje ◽  
Daan Sondag ◽  
Hidde Elferink ◽  
...  

<p>In this manuscript we describe a modular pathway to synthesize biologically relevant (–)-<i>trans</i>-Δ<sup>8</sup>-THC derivatives, which can be used to modulate the pharmacologically important CB<sub>1</sub> and CB<sub>2</sub> receptors. This pathway involves a one-pot Friedel-Crafts alkylation/cyclization protocol, followed by Suzuki-Miyaura cross-coupling reactions and gives rise to a series of new Δ<sup>8</sup>-THC derivatives. In addition, we demonstrate using extensive NMR evidence that similar halide-substituted Friedel-Crafts alkylation/cyclization products in previous articles were wrongly assigned as the para-isomers, which also has consequence for the assignment of the subsequent cross-coupled products and interpretation of their biological activity. </p> <p>Considering the importance of the availability of THC derivatives in medicinal chemistry research and the fact that previously synthesized compounds were wrongly assigned, we feel this research is describing a straightforward pathway into new cannabinoids.</p>


2006 ◽  
Vol 4 (3) ◽  
pp. 375-402 ◽  
Author(s):  
Masataka Watanabe ◽  
Taisuke Matsumoto ◽  
Shuntaro Mataka ◽  
Thies Thiemann

Abstract17-Thienyl-and 17-benzo[b]thienyl-3-hydroxyestra-1,3,5(10),16-tetraenes were synthesized by either sequential or one-pot Suzuki cross-coupling and Wittig olefination reactions. At 160 °C, heteroaryl substituted steroids were observed to undergo thermal intramolecular cyclization to produce E-ring heteroareno-annelated estranes.


Author(s):  
Hannah E. Burdge ◽  
Takuya Oguma ◽  
Takahiro Kawajiri ◽  
Ryan Shenvi

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>


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